When pressing the break there is a lot of play - press it hard and they are solid! Anyone else experience this or have any advice - gonna book it in for a once over in the new year! 

These cars seem to be prone to suffering from firewall flex. Essentially, the brake master cylinder assembly is attached to the firewall (between the cabin and engine bay) and over time, with pressure on the brake pedal, the wall can flex resulting in a soft feel on the pedal.

Fairly well documented issue with the STi and most people do this (as have I) -

May or may not be the cause of your issue, but something to consider?